Washington, May 25 (Inditop): One of several astonishing reconstructions of ocean life in olden days suggests that about the ocean around New Zealand teemed with about 27,000 southern right whales, about 30 times as many as today, before oil hunters started to whaling in the early 1800s.
The researchers set to make a presentation on the reconstruction at a Census of Marine Life conference, which runs from May 26 to 28, say that at about the same time, large pods of blue whales and orcas, blue sharks and thresher sharks darkened the waters off Cornwall, England, herds of harbour porpoise pursued fish upriver, and dolphins regularly played in waters inshore.
Census researchers are using such diverse sources as old ship logs, literary texts, tax accounts, newly translated legal documents and even mounted trophies to piece together images of fish of such sizes, abundance and distribution in ages past that they stagger modern imaginations.
They are also documenting the timelines over which those giant marine life populations declined.
Researchers James Barrett and Jen Harland of Cambridge University, Cluny Johnstone of York University, and Mike Richards of Germany-based Max Planck Institute reckon that a shift from eating locally-caught freshwater to marine fish species occurred around 1000 AD.
Their surmise is said to be consistent with analyses of scientifically-dated fish remains and historical data from England and northwestern Europe showing smaller freshwater fish and fewer species availability in early medieval times, likely caused by increased exploitation and pollution.
Meanwhile, Maria Lucia De Nicolo of the University of Bologna has established that new fishing boats and equipment invented in the 1500s made it possible to venture from coastal to deep sea fishing.
She says that the real revolution in marine fishing happened in the mid-1600s when pairs of boats began dragging a net.
Andy Rosenberg of the University of New Hampshire, a leader of the Census’ History of Marine Animal Population (HMAP) project and chair of the conference, says that new insights allowed by centuries of information are upending modern notions of “natural” marine life sizes, abundance, habitats and vulnerability, and causing authorities to revisit marine baselines.
The researchers believe that these insights may turn out to be useful for policy makers, who plan to use the results as a realistic baseline against which the current and future status of the marine ecosystem can be gauged.
Ian Poiner, Chair of the Census Scientific Steering Committee, says: “The insights emerging from this research of the past provide a new context for contemporary ocean management. Understanding the magnitude and drivers of change long ago is essential to accurately interpret today’s trends and to make future projections.”
rounak